1. Field of the Invention
The present invention relates to a device embedding a two-dimensional code in an original document using a low-visibility information embedding method, and in particular to a device having a function of adjusting a two-dimensional code before embedding (printing) the two-dimensional code in an original document.
2. Description of the Related Art
In recent years, there has frequently occurred an incident where confidential information, such as customer information held by a company, illegally flows out of the company, which has become a big social problem. In order to prevent such an incident from occurring, many companies take countermeasures to prevent confidential information from flowing out of the companies, such as imposing an access restriction on confidential information converted to electronic form and providing a monitor for a firewall. In addition, some companies take actions such as prohibiting employees from bringing a private portable memory such as a notebook PC or a USB memory into the companies and prohibiting employees from taking information equipment possessed by the companies out of the companies without permission. In this way, companies plan to protect confidential information converted to electronic form by taking various security measures. On the other hand, an employee generally can take a document out of the company, so that when confidential information is printed on paper as part of a document, it is difficult to prevent the document from being illegally taken out of the company. A document which has been illegally taken out of a company may be copied or converted to electronic form using a scanner to make many copies of the document and the copies may be distributed to the general public. It is therefore necessary for companies to take measures to protect confidential information printed in a paper document in addition to strengthening the management of confidential information converted to electronic form, in order to ensure the protection and management of confidential information.
In order to protect confidential information printed in a paper document, various methods have been previously proposed. As one of the methods, a method exists for printing an image and embedding printing/coping history information in an original document in the form of a two-dimensional code when printing the image, using a technology of embedding/extracting information with a two-dimensional code. According to this method, a confidential information manager is able to identify a person who took out a document or a person who took a copy of the document by getting the document or a copy of it and analyzing a two-dimensional code embedded therein. It can be considered that this serves as a big deterrent against bringing out a document in which confidential information is printed and copying the document. Furthermore, as another method, a method exists for printing an image and embedding copy restriction information (copy permission, copy prohibition, or the like) in an original document in the form of a two-dimensional code when printing the image, using a technology of embedding/extracting information with a two-dimensional code (Japanese Patent Laid-Open No. 2003-280469). According to this method, a copying machine having a function using the technology of embedding/extracting information is able to extract the two-dimensional code from the original document, analyze it to obtain copy restriction information, and control the continuation or stop of copying every page on the basis of the copy restriction information when copying the original document. Furthermore, the copying machine is able to control copying so that only an authorized user is able to make a copy by embedding the user information or password information of a person who has been admitted to make a copy.
In this way, the methods described above include a step of embedding additional information (printing/copying history information, copy restriction information, and the like) in an original document in the form of a two-dimensional code, and a step of extracting the two-dimensional code embedded in the original document and analyzing it.
The method of embedding additional information in an original document in the form of a two-dimensional code might not be able to accurately extract the two-dimensional code from the original document or accurately analyze the extracted two-dimensional code from the reasons given below.                A two-dimensional code is not accurately embedded in an original document due to the condition of deposition of toner at the time of embedding the two-dimensional code in the original document (at the time of printing the two-dimensional code) or due to a method of handling the original document.        A two-dimensional barcode can not be accurately extracted by the restriction of the scanning accuracy of a scanner scanning an original document in which the two-dimensional code is embedded.        When a portion on which a two-dimensional code and an image are printed overlapping each other exists, the two-dimensional code can not be accurately extracted from the portion.        
In this way, in the conventional methods, it is determined whether a two-dimensional code embedded in an original document is appropriate or not for the first time at a step of extracting the two-dimensional code embedded in the original document and analyzing it. In other words, the conventional methods have a problem that it can not be determined at a step of embedding a two-dimensional code whether a printout result effective for security has been obtained, that is, whether an appropriate two-dimensional code has been embedded.